1,720,964 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Hysteresis in Magnetocaloric Materials:An experimental and modelling approach
Get PDFI denne afhandling behandles effekten af hysterese på magnetokaloriske materialers egenskaber samt dens indflydelse på ydeevnen i magnetiske kølingsapparater. Dette gøres gennem et kombineret eksperimentelt og modelleringsstudie af de to første ordens magnetokaloriske materialer MnFe(P,As) og Gd5Si2Ge2. Den eksperimentelle karakterisering af den magnetokaloriske effekt (MCE) i disse materialer er udført ved brug af konventionelle indirekte metoder, baseret på magnetometri og kalorimetri, samt nyudviklede direkte metoder. Bestemmelsen af MCE’en ved en ændring af magnetfeltet er i princippet givet ved materialets temperaturafhængige isofelt entropikurver, bestemt ved det lave startfelt og det høje slutfelt. Men i første ordens materialer opnås termiske entropi hysteresekurver gennem karakteriseringen, svarende til målinger udført under øgning og sænkning af temperaturen. Indirekte metoder til bestemmelse af MCE’en, så som Maxwell relationen eller kalorimetriske målinger udført kun ved enten opvarmning eller nedkølning, estimerer MCE’en som den reversible forskel mellem de to isofelt opvarmningskurver eller nedkølningskurver. Her vises det, at direkte målemetoder angiver at den korrekte MCE er givet ved forskellen mellem opvarmningskurven ved lavt felt og nedkølningskurven ved højt felt, hvilket kan reducere den estimerede MCE betragteligt. Data fra materialekarakteriseringen bruges som fundament til modeller af Preisach typen. Disse modeller er velegnede til at håndtere de ude-af-ligevægtsforhold der eksisterer i første ordens materialer, ved at tage højde for materialeegenskabernes afhængighed af den termiske og magnetiske historie, samt varmeudvikling i forbindelse med hysterestab. Både MnFe(P,As) og Gd5Si2Ge2 modelleres og det ses at Preisach-tilgangen er anvendelig til at kunne genskabe materialernes opførsel. Modellen af Gd5Si2Ge2 er baseret på detaljerede first order reversal curves, der tager højde for både reversible og irreversible egenskaber. Det illustreres at modellen kan reproducere en serie af uafhængigt udførte eksperimenter. Preisach modellerne anvendes til at simulere materialernes opførsel under realistiske anvendelsesforhold i AMR-lignende cyklusser. Resultaterne af dette bekræfter observationerne fra de direkte eksperimenter, at under AMR lignende forhold er den tilgængelige MCE bundet af det minimale areal i entropi-temperatur rummet; rummet mellem minimumfeltets opvarmningskurve og maksimumfeltets nedkølningskurve. Varmeudviklingen forårsaget af hysterese i en AMR-lignende cyklus sat i gang ved en given temperature demonstreres at være lig den tilsvarende isoterme magnetiserings hysteresekurve. Derudover ses det, at MCE’en er tæt korreleret med hysteresen. Dette åbner op for en relativ simpel implementering af magnetisk hysteresetab i numeriske AMR systemmodeller: enten ved brug af data fra målte isoterme hysteresekurver eller endnu simplere ved at tilføje en varmeproduktion der er skaleret efter den kendte MCE. På grund af historieafhængigheden i materialer med hysterese, skal eksperimentelle procedurer grundigt analyseres. Her demonstreres det, at magnetiseringsmålinger kan lide af uforudsete effekter, på grund af uvarsomme ændringer af magnetfelt og temperature. For høje magnetfeltramper inducerer kunstige hystereseeffekter på grund af MCE’en, selv ved lave ramperater. Aggressiv temperaturkontrol kan føre til oscillationer omkring sættemperaturer. Dette kan føre til partielle hysteresekurver, hvilket generelt vil underestimere den målte termiske hysterese. Derudover illustreres det, at man skal være varsom ved udførslen af målinger der foregår ved ikke konstante felter, som er tilfældet i direkte målinger af MCE’en. Ved bestemmelse af den temperaturafhængige MCE kan forskellige resultater opnås ved målinger foretaget under opvarmning og nedkølning. Nedkølningsmetoden vil generelt bevirke at resultaterne er overestimerede, hvorimod resultater opnået ved opvarmningsmetoden er repræsentativ for MCE i realistiske anvendelsesforhold.In this thesis the effects of hysteresis on magnetocaloric material properties and their performance in magnetic refrigeration devices are investigated. This is done through an experimental and model study of first order magnetocaloric materials MnFe(P,As) and Gd5Si2Ge2. The experimental characterization of the magnetocaloric effect (MCE) in these materials is done through conventional indirect magnetometric and calorimetric methods, as well as newly developed direct methods. The determination of the MCE due to a magnetic field change is in principle given by the isofield material entropy curves, obtained at the initial low and final high field. However, in first order materials thermal entropy hysteresis loops are obtained through characterization, corresponding to measurements done in an increasing and a decreasing temperature mode. Indirectly determining the MCE through the use of the Maxwell relation or calorimetric measurements done only in a heating or cooling mode, estimate the MCE as the reversible difference between the set isofield heating-heating or cooling-cooling entropy curves. Here it is shown that direct measurements suggest that the real MCE is given by the difference between the low field heating and high field cooling entropy curves, which can reduce the MCE estimate significantly. The experimental data obtained through the material characterization is used as a foundation for Preisach type models. This type of model is suited to handle the non-equilibrium nature of first order materials, taking the magnetic and thermal history dependence of material properties into account, as well as the heat production due to hysteretic losses. MnFe(P,As) and Gd5Si2Ge2 compounds are modelled and it is found that the Preisach approach is suitable to reproduce material behavior in both cases. The Gd5Si2Ge2 model is based on detailed first order reversal curve data, taking both reversible and irreversible properties into account, and is able to reproduce a series of independent experimental results. The Preisach models are applied to simulate material behavior under realistic application conditions in AMR-type cycles. The findings support those of the direct MCE measurements, namely that under AMR-type conditions the available MCE is bound by low field heating and high field cooling entropy curves. The heat production due to hysteresis in an AMR-type cycle initiated at a given temperature is found to be equal to that of the corresponding isothermal magnetization hysteresis loop. Furthermore the MCE is seen to be correlated to the hysteresis. This allows for relatively simple implementation of magnetic hysteresis losses in numerical AMR system models: either from measured isothermal magnetization curves or simply by adding heat production in the form of a suitably scaled MCE. Due to the history dependence of hysteretic materials, experimental procedures need careful analysis. It is demonstrated that magnetization measurements can suffer from unintended effects due uncareful change of the magnetic field and temperature. Too high magnetic field ramps in isothermal magnetization experiments can induce extrinsic hysteresis effects due to the MCE destroying the isothermal conditions, even at relatively low ramp rates. Aggressive temperature control can lead to oscillations around temperature set points, which is demonstrated to induce partial hysteresis loop behavior that will generally underestimate thermal hysteresis. Furthermore it is shown that care should be taken in non-isofield type experiments, as is the case for direct MCE experiments. Measuring the temperature dependence of the MCE can yield different results in heating or cooling modes. Cooling mode measurements will tend to be overestimated, whereas the heating mode results are representative of the realistic MCE available in application conditions
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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